(1) Field of the Invention.
The present invention relates to a drive control system.
More specifically, the invention concerns a system of the above kind particularly studied and realised to vary resistance of steering wheel, a rudder or like of a vehicle, such as a car, a boat, an aircraft and like, but also console of a video game or of simulation apparatus, the latter being always more frequently used in developing cars, modifying the feeling felt while driving a vehicle by a driver.
In the following, the specification will be addressed, according to the specific cases, particularly to the control and driving of a boat or of a car, but it is well evident that the same must not be considered limited to this specific use.
(2) Description of Related Art
As it is well known, different kind of steering systems exist which are installed in different kind of vehicles. Steering systems are, as it is well known, driving assisting apparatus which are useful in different manoeuvring conditions.
Usually, steering systems have, on one side the aim of reducing the physical stress while controlling the vehicle in the different driving situations (for example power-steering for cars or hydro guide for trucks), and on the other side they should give a much more realistic control feeling, to give to the driver brain all the information about attitude and stability of the vehicle driven, in order to ensure maximum control and safety.
Electric/electronic steering systems presently available on the nautical market—but also in the industrial field—implement DC brushless electric motors. Said systems are also provided with electronic control units (ECU) piloted by sophisticated software.
Said brushless DC motors are directly mounted on the steering wheel support, in lieu of the steering wheel column, and can satisfy many driving comfort requisites. However, they do not always permit a realistic and comfortable guide in every manoeuvring situation.
For example, in the automotive field, traditional steering systems available on the market since many time can give a kind of feedback of the hydraulic/mechanic type thanks to the use of hydraulic pumps.
An advantage of this kind of systems is that of conferring a very fluid and continuous control and guide feeling, thanks to a purely mechanical control transmission, without mediation of electric systems.
Always in the automotive field, the so called modern/hybrid steering systems adopt, for example, as additional module, a stepwise DC or electric brushless motor with ratio gear directly mounted on the rack. However, also in this case, obtained control feeling is not always the best one possible.
Moreover, it must be remembered that rules exist in the automotive field that suitably adjust, under a safety point of view, elimination of fixed mechanical parts between steering wheel and hub holders.
It must be pointed out that this kind of limitative rules do not exist in the nautical field, where, as also for industrial fields such as shunters, cranes, lifting devices, heavy vehicles without number plate, ecc., different kind of electric steering systems are present.
In nautical field, said electric systems generically have an electric steering wheel, for example comprised of a unit with a brushless DC motor and a epicyclic reduction gear, which is used as direct support of the steering wheel and stepwise motor (stepper) acting in the rotative and submerged part.
Known solutions adapts the steering wheel rotative hardness, in different guide situations, e.g. by implementing DC brushless motors. However, said systems have different adjustment problems. In fact, if motor overheating occurs when torque must be braked (regardless this occurs to increase steering wheel rotation force or to create “virtual/electric stops”), heat generated during the “inertia braking” operations could also cause problems to the DC brushless motor thermal protection.